Thin film metal oxynitride semiconductors

Abstract

The present invention generally relates to a semiconductor film and a method of depositing the semiconductor film. The semiconductor film comprises oxygen, nitrogen, and one or more elements selected from the group consisting of zinc, cadmium, gallium, indium, and tin. Additionally, the semiconductor film may be doped. The semiconductor film may be deposited by applying an electrical bias to a sputtering target comprising the one or more elements selected from the group consisting of zinc, cadmium, gallium, indium, and tin, and introducing a nitrogen containing gas and an oxygen containing gas. The sputtering target may optionally be doped. The semiconductor film has a mobility greater than amorphous silicon. After annealing, the semiconductor film has a mobility greater than polysilicon.

The invention claimed is: 
     
       1. A sputtering method comprising:
 flowing an oxygen containing gas, an inert gas, and a nitrogen containing gas into a processing chamber; 
 applying a DC electrical bias to a sputtering target comprising a dopant and one or more metals selected from the group consisting of zinc, gallium, cadmium, indium, and tin; 
 depositing a semiconductor layer on a substrate, the semiconductor layer comprising the one or more metals, the dopant, oxygen, and nitrogen, wherein at least a portion of the semiconductor layer comprises an oxynitride compound; 
 increasing the ratio of the flow rates of the nitrogen containing gas to the oxygen containing gas during deposition of the semiconductor layer to increase electron mobility of the semiconductor layer, wherein the ratio of the flow rates of the nitrogen containing gas to the oxygen containing gas is above about 10:1, wherein the oxygen containing gas has a flow rate of greater than 10 sccm, and wherein the semiconductor layer has an electron mobility that is greater than 20 times an electron mobility of amorphous silicon; and 
 annealing the deposited semiconductor layer at a temperature above about 250 degrees Celsius, wherein the semiconductor layer has an electron mobility of greater than 90 cm 2 /V-s. 
 
     
     
       2. The method of  claim 1 , wherein the semiconductor layer comprises two or more metals selected from the group consisting of zinc, gallium, cadmium, indium, and tin. 
     
     
       3. The method of  claim 1 , wherein the dopant is selected from the group consisting of aluminum, tin, gallium, calcium, silicon, titanium, copper, germanium, indium, nickel, chromium, vanadium, magnesium, and combinations thereof. 
     
     
       4. The method of  claim 1 , wherein at least a portion of the semiconductor layer further comprises a nitride compound. 
     
     
       5. The method of  claim 1 , wherein the semiconductor layer is amorphous or has a nanocrystalline structure. 
     
     
       6. The method of  claim 1 , wherein the nitrogen containing gas and the oxygen containing gas are separate gases.